RE: [EDITS] special values

[Roger Crew <rfc@MICROSOFT.com>]

[...let me tell you sometime how much I hate Microsoft Exchange, that
last message got sent out accidentally, before I finished editing that
last paragraph...]

My take:

  If there are any multiline values, the message must include a
  keyword named _data-tag.  The _data_tag value, in combination
  with the keywords for the multiline values, will be used to flag
  subsequent lines.  Data tags are case-sensitive (implementations must
not vary the
  case of any alphabetic characters in the tag between the _data-tag:
  argument and the multiline value, or within the multiline value
  itself), and may be any string of characters representable as an
  <unquoted-string> in the MCP grammar below.